Value of ictal and interictal epileptiform discharges and high frequency oscillations for delineating the epileptogenic zone in patients with focal cortical dysplasia

Working memory (WM) deficits are pervasive co-morbidities of epilepsy. Although the pathophysiological mechanisms underpinning these impairments remain elusive, it is thought that WM depends on oscillatory interactions within and between nodes of large-scale functional networks. These include the hippocampus and default mode network as well as the prefrontal cortex and frontoparietal central executive network. Here, we review the functional roles of neural oscillations in subserving WM and the putative mechanisms by which epilepsy disrupts normative activity, leading to aberrant oscillatory signatures. We highlight the particular role of interictal epileptic activity, including interictal epileptiform discharges and high frequency oscillations (HFOs) in WM deficits. We also discuss the translational opportunities presented by greater understanding of the oscillatory basis of WM function and dysfunction in epilepsy, including potential targets for neuromodulation.

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Dynamic Statistical Parametric Mapping for Analyzing the Magnetoencephalographic Epileptiform Activity in Patients With Epilepsy

Journal of Child Neurology ◽

10.1177/08830738040190031601 ◽

2004 ◽

Vol 19 (3) ◽

pp. 363-369

Author(s):

Hideaki Shiraishi ◽

Steven M. Stufflebeam ◽

Susanne Knake ◽

Seppo P. Ahlfors ◽

Akira Sudo ◽

...

Keyword(s):

Focal Cortical Dysplasia ◽

Epileptiform Activity ◽

Rapid Change ◽

Statistical Parametric Mapping ◽

Cortical Dysplasia ◽

Parametric Mapping ◽

Epileptiform Discharges ◽

Interictal Epileptiform Discharges ◽

L2 Norm ◽

Patients With Epilepsy

Our current purpose is to evaluate the applicability of dynamic statistical parametric mapping, a novel method for localizing epileptiform activity recorded with magnetoencephalography in patients with epilepsy. We report four pediatric patients with focal epilepsies. Magnetoencephalographic data were collected with a 306-channel whole-head helmet-shaped sensor array. We calculated equivalent current dipoles and dynamic statistical parametric mapping movies of the interictal epileptiform discharges that were based in the minimum-L2 norm estimate, minimizing the square sum of the dipole element amplitudes. The dynamic statistical parametric mapping analysis of interictal epileptiform discharges can demonstrate the rapid change and propagation of interical epileptiform discharges. According to these findings, specific epileptogenic lesion—focal cortical dysplasia could be found and patients could be operated on successfully. The presurgical analysis of interictal epileptiform discharges using dynamic statistical parametric mapping seems to be promising in patients with a possible underlying focal cortical dysplasia and might help to guide the placement of invasive electrodes. ( J Child Neurol 2005;20:363—369).

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Recent Advances in Epilepsy Surgery and Achieving Best Outcomes Using High-Frequency Oscillations, Diffusion Tensor Imaging, Magnetoencephalography, Intraoperative Neuromonitoring, Focal Cortical Dysplasia, and Bottom of Sulcus Dysplasia

Neurosurgery ◽

10.1093/neuros/nyx239 ◽

2017 ◽

Vol 64 (CN_suppl_1) ◽

pp. 1-10 ◽

Cited By ~ 8

Author(s):

Nessa Timoney ◽

James T. Rutka

Keyword(s):

Diffusion Tensor Imaging ◽

Epilepsy Surgery ◽

High Frequency ◽

Diffusion Tensor ◽

Focal Cortical Dysplasia ◽

Cortical Dysplasia ◽

Intraoperative Neuromonitoring ◽

High Frequency Oscillations ◽

Recent Advances

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PO18-WE-17 Interictal high-frequency oscillations indicate seizure onset zone in patients with focal cortical dysplasia

Journal of the Neurological Sciences ◽

10.1016/s0022-510x(09)70946-3 ◽

2009 ◽

Vol 285 ◽

pp. S248

Author(s):

M. Brazdil ◽

J. Halamek ◽

P. Jurak ◽

P. Daniel ◽

R. Kuba ◽

...

Keyword(s):

High Frequency ◽

Focal Cortical Dysplasia ◽

Cortical Dysplasia ◽

Seizure Onset ◽

High Frequency Oscillations ◽

Seizure Onset Zone

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Interictal high-frequency oscillations indicate seizure onset zone in patients with focal cortical dysplasia

Epilepsy Research ◽

10.1016/j.eplepsyres.2010.03.003 ◽

2010 ◽

Vol 90 (1-2) ◽

pp. 28-32 ◽

Cited By ~ 28

Author(s):

Milan Brázdil ◽

Josef Halámek ◽

Pavel Jurák ◽

Pavel Daniel ◽

Robert Kuba ◽

...

Keyword(s):

High Frequency ◽

Focal Cortical Dysplasia ◽

Cortical Dysplasia ◽

Seizure Onset ◽

High Frequency Oscillations ◽

Seizure Onset Zone

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Surgical outcome and prognostic factors in epilepsy patients with MR-negative focal cortical dysplasia

PLoS ONE ◽

10.1371/journal.pone.0249929 ◽

2021 ◽

Vol 16 (4) ◽

pp. e0249929

Author(s):

Min Jae Seong ◽

Su Jung Choi ◽

Eun Yeon Joo ◽

Young-Min Shon ◽

Dae-Won Seo ◽

...

Keyword(s):

Prognostic Factors ◽

Surgical Outcomes ◽

Focal Cortical Dysplasia ◽

Cortical Dysplasia ◽

Type I ◽

Epileptiform Discharges ◽

Interictal Epileptiform Discharges ◽

Neuroimaging Data ◽

Magnetic Resonance Imaging Mri ◽

Drug Resistant Epilepsy

Objective Focal cortical dysplasia (FCD) represents a heterogeneous group of disorders of the cortical formation and is one of the most common causes of epilepsy. Magnetic resonance imaging (MRI) is the modality of choice for detecting structural lesions, and the surgical prognosis in patients with MR lesions is favorable. However, the surgical prognosis of patients with MR-negative FCD is unknown. We aimed to evaluate the long-term surgical outcomes and prognostic factors in MR-negative FCD patients through comprehensive presurgical data. Methods We retrospectively reviewed data from 719 drug-resistant epilepsy patients who underwent resective surgery and selected cases in which surgical specimens were pathologically confirmed as FCD Type I or II. If the epileptogenic focus and surgical specimens were obtained from brain areas with a normal MRI appearance, they were classified as MR-negative FCD. Surgical outcomes were evaluated at 2 and 5 years, and clinical, neurophysiological, and neuroimaging data of MR-negative FCD were compared to those of MR-positive FCD. Results Finally, 47 MR-negative and 34 MR-positive FCD patients were enrolled in the study. The seizure-free rate after surgery (Engel classification I) at postoperative 2 year was 59.5% and 64.7% in the MR-negative and positive FCD groups, respectively (p = 0.81). This rate decreased to 57.5% and 44.4% in the MR-negative and positive FCD groups (p = 0.43) at postoperative 5 years. MR-negative FCD showed a higher proportion of FCD type I (87.2% vs. 50.0%, p = 0.001) than MR-positive FCD. Unilobar cerebral perfusion distribution (odds ratio, OR 5.41) and concordance of interictal epileptiform discharges (OR 5.10) were significantly associated with good surgical outcomes in MR-negative FCD. Conclusion In this study, MR-negative and positive FCD patients had a comparable surgical prognosis, suggesting that comprehensive presurgical evaluations, including multimodal neuroimaging studies, are crucial for obtaining excellent surgical outcomes even in epilepsy patients with MR-negative FCD.

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